It is very necessary in machinery and other elements which use parts having relative rotation, to protect interior mechanisms from deleterious effects which may be caused by the entry of contaminates and particulate matter from the surrounding environment.
Many prior art seals have been developed to seal the interface of relatively rotatable elements. Such seals usually comprise a stiff elastomeric ring which is molded and carried in a casing in one of the relatively movable elements, and having a seal lip which bears on a precision diameter of the other member. Many times it is not possible or desirable to seal a movable member on a diameter, but rather is preferable to seal on a face of a rotatable member. Face seals on rotating members are generally very expensive and complex in construction as well as being sometimes difficult to manufacture, since they usually comprise a spring-loaded, low friction, element in a casing which bears against the smooth sealing face on the relatively rotating member, and such sealing devices do not readily adapt themselves for relative axial movement between a shaft and a housing, because they are designed for installation to a preset dimension only.
The prior art large diameter seals are generally very expensive to purchase since they involve special molds to create the sealing element and the mold set up charges are significant, especially for non-standard custom seals. The face seals which are available are very expensive as well and also require a substantial space and precision to mount them.
Applicant has obviated the difficulty involved in the prior art devices for sealing large surfaces which must rotate relative to a stationary housing and must have provision for axial movement of the surface toward and away from the housing.
It is therefore an object of the within invention to provide a seal which is inexpensively manufactured for a variety of installations.
It is another object of the within invention to provide a seal which is capable of sealing relatively rotating bodies yet permits the one body to move toward and away from the other body while effecting a seal between the two, requiring only a low level of precision between the elements.